From 8e0cbf356377fabac47a027dd176cd1cacc5fc01 Mon Sep 17 00:00:00 2001 From: Mark Pearson Date: Tue, 29 Dec 2020 19:18:25 -0500 Subject: [PATCH 1/5] Documentation: Add documentation for new platform_profile sysfs attribute On modern systems the platform performance, temperature, fan and other hardware related characteristics are often dynamically configurable. The profile is often automatically adjusted to the load by some automatic-mechanism (which may very well live outside the kernel). These auto platform-adjustment mechanisms often can be configured with one of several 'platform-profiles', with either a bias towards low-power consumption or towards performance (and higher power consumption and thermals). Introduce a new platform_profile sysfs API which offers a generic API for selecting the performance-profile of these automatic-mechanisms. Co-developed-by: Hans de Goede Signed-off-by: Mark Pearson Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- .../ABI/testing/sysfs-platform_profile | 24 +++++++++++ Documentation/userspace-api/index.rst | 1 + .../userspace-api/sysfs-platform_profile.rst | 42 +++++++++++++++++++ 3 files changed, 67 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-platform_profile create mode 100644 Documentation/userspace-api/sysfs-platform_profile.rst diff --git a/Documentation/ABI/testing/sysfs-platform_profile b/Documentation/ABI/testing/sysfs-platform_profile new file mode 100644 index 000000000000..9d6b89b66cca --- /dev/null +++ b/Documentation/ABI/testing/sysfs-platform_profile @@ -0,0 +1,24 @@ +What: /sys/firmware/acpi/platform_profile_choices +Date: October 2020 +Contact: Hans de Goede +Description: This file contains a space-separated list of profiles supported for this device. + + Drivers must use the following standard profile-names: + + ============ ============================================ + low-power Low power consumption + cool Cooler operation + quiet Quieter operation + balanced Balance between low power consumption and performance + performance High performance operation + ============ ============================================ + + Userspace may expect drivers to offer more than one of these + standard profile names. + +What: /sys/firmware/acpi/platform_profile +Date: October 2020 +Contact: Hans de Goede +Description: Reading this file gives the current selected profile for this + device. Writing this file with one of the strings from + platform_profile_choices changes the profile to the new value. diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index acd2cc2a538d..d29b020e5622 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -24,6 +24,7 @@ place where this information is gathered. ioctl/index iommu media/index + sysfs-platform_profile .. only:: subproject and html diff --git a/Documentation/userspace-api/sysfs-platform_profile.rst b/Documentation/userspace-api/sysfs-platform_profile.rst new file mode 100644 index 000000000000..c33a71263d9e --- /dev/null +++ b/Documentation/userspace-api/sysfs-platform_profile.rst @@ -0,0 +1,42 @@ +===================================================================== +Platform Profile Selection (e.g. /sys/firmware/acpi/platform_profile) +===================================================================== + +On modern systems the platform performance, temperature, fan and other +hardware related characteristics are often dynamically configurable. The +platform configuration is often automatically adjusted to the current +conditions by some automatic mechanism (which may very well live outside +the kernel). + +These auto platform adjustment mechanisms often can be configured with +one of several platform profiles, with either a bias towards low power +operation or towards performance. + +The purpose of the platform_profile attribute is to offer a generic sysfs +API for selecting the platform profile of these automatic mechanisms. + +Note that this API is only for selecting the platform profile, it is +NOT a goal of this API to allow monitoring the resulting performance +characteristics. Monitoring performance is best done with device/vendor +specific tools such as e.g. turbostat. + +Specifically when selecting a high performance profile the actual achieved +performance may be limited by various factors such as: the heat generated +by other components, room temperature, free air flow at the bottom of a +laptop, etc. It is explicitly NOT a goal of this API to let userspace know +about any sub-optimal conditions which are impeding reaching the requested +performance level. + +Since numbers on their own cannot represent the multiple variables that a +profile will adjust (power consumption, heat generation, etc) this API +uses strings to describe the various profiles. To make sure that userspace +gets a consistent experience the sysfs-platform_profile ABI document defines +a fixed set of profile names. Drivers *must* map their internal profile +representation onto this fixed set. + +If there is no good match when mapping then a new profile name may be +added. Drivers which wish to introduce new profile names must: + + 1. Explain why the existing profile names canot be used. + 2. Add the new profile name, along with a clear description of the + expected behaviour, to the sysfs-platform_profile ABI documentation. From a2ff95e018f1d2bc816f3078d5110a655e355f18 Mon Sep 17 00:00:00 2001 From: Mark Pearson Date: Tue, 29 Dec 2020 19:18:26 -0500 Subject: [PATCH 2/5] ACPI: platform: Add platform profile support This is the initial implementation of the platform-profile feature. It provides the details discussed and outlined in the sysfs-platform_profile document. Many modern systems have the ability to modify the operating profile to control aspects like fan speed, temperature and power levels. This module provides a common sysfs interface that platform modules can register against to control their individual profile options. Signed-off-by: Mark Pearson Reviewed-by: Hans de Goede [ rjw: Use full words in enum values names ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/Kconfig | 17 +++ drivers/acpi/Makefile | 1 + drivers/acpi/platform_profile.c | 181 +++++++++++++++++++++++++++++++ include/linux/platform_profile.h | 39 +++++++ 4 files changed, 238 insertions(+) create mode 100644 drivers/acpi/platform_profile.c create mode 100644 include/linux/platform_profile.h diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index edf1558c1105..5ddff93e38c2 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -326,6 +326,23 @@ config ACPI_THERMAL To compile this driver as a module, choose M here: the module will be called thermal. +config ACPI_PLATFORM_PROFILE + tristate "ACPI Platform Profile Driver" + default m + help + This driver adds support for platform-profiles on platforms that + support it. + + Platform-profiles can be used to control the platform behaviour. For + example whether to operate in a lower power mode, in a higher + power performance mode or between the two. + + This driver provides the sysfs interface and is used as the registration + point for platform specific drivers. + + Which profiles are supported is determined on a per-platform basis and + should be obtained from the platform specific driver. + config ACPI_CUSTOM_DSDT_FILE string "Custom DSDT Table file to include" default "" diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 076894a3330f..52b627c7f977 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -79,6 +79,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT) += pci_slot.o obj-$(CONFIG_ACPI_PROCESSOR) += processor.o obj-$(CONFIG_ACPI) += container.o obj-$(CONFIG_ACPI_THERMAL) += thermal.o +obj-$(CONFIG_ACPI_PLATFORM_PROFILE) += platform_profile.o obj-$(CONFIG_ACPI_NFIT) += nfit/ obj-$(CONFIG_ACPI_NUMA) += numa/ obj-$(CONFIG_ACPI) += acpi_memhotplug.o diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c new file mode 100644 index 000000000000..91be50a32cc8 --- /dev/null +++ b/drivers/acpi/platform_profile.c @@ -0,0 +1,181 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +/* Platform profile sysfs interface */ + +#include +#include +#include +#include +#include +#include + +static const struct platform_profile_handler *cur_profile; +static DEFINE_MUTEX(profile_lock); + +static const char * const profile_names[] = { + [PLATFORM_PROFILE_LOW_POWER] = "low-power", + [PLATFORM_PROFILE_COOL] = "cool", + [PLATFORM_PROFILE_QUIET] = "quiet", + [PLATFORM_PROFILE_BALANCED] = "balanced", + [PLATFORM_PROFILE_PERFORMANCE] = "performance", +}; +static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST); + +static ssize_t platform_profile_choices_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int len = 0; + int err, i; + + err = mutex_lock_interruptible(&profile_lock); + if (err) + return err; + + if (!cur_profile) { + mutex_unlock(&profile_lock); + return -ENODEV; + } + + for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) { + if (len == 0) + len += sysfs_emit_at(buf, len, "%s", profile_names[i]); + else + len += sysfs_emit_at(buf, len, " %s", profile_names[i]); + } + len += sysfs_emit_at(buf, len, "\n"); + mutex_unlock(&profile_lock); + return len; +} + +static ssize_t platform_profile_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED; + int err; + + err = mutex_lock_interruptible(&profile_lock); + if (err) + return err; + + if (!cur_profile) { + mutex_unlock(&profile_lock); + return -ENODEV; + } + + err = cur_profile->profile_get(&profile); + mutex_unlock(&profile_lock); + if (err) + return err; + + /* Check that profile is valid index */ + if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names)))) + return -EIO; + + return sysfs_emit(buf, "%s\n", profile_names[profile]); +} + +static ssize_t platform_profile_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int err, i; + + err = mutex_lock_interruptible(&profile_lock); + if (err) + return err; + + if (!cur_profile) { + mutex_unlock(&profile_lock); + return -ENODEV; + } + + /* Scan for a matching profile */ + i = sysfs_match_string(profile_names, buf); + if (i < 0) { + mutex_unlock(&profile_lock); + return -EINVAL; + } + + /* Check that platform supports this profile choice */ + if (!test_bit(i, cur_profile->choices)) { + mutex_unlock(&profile_lock); + return -EOPNOTSUPP; + } + + err = cur_profile->profile_set(i); + mutex_unlock(&profile_lock); + if (err) + return err; + return count; +} + +static DEVICE_ATTR_RO(platform_profile_choices); +static DEVICE_ATTR_RW(platform_profile); + +static struct attribute *platform_profile_attrs[] = { + &dev_attr_platform_profile_choices.attr, + &dev_attr_platform_profile.attr, + NULL +}; + +static const struct attribute_group platform_profile_group = { + .attrs = platform_profile_attrs +}; + +void platform_profile_notify(void) +{ + if (!cur_profile) + return; + sysfs_notify(acpi_kobj, NULL, "platform_profile"); +} +EXPORT_SYMBOL_GPL(platform_profile_notify); + +int platform_profile_register(const struct platform_profile_handler *pprof) +{ + int err; + + mutex_lock(&profile_lock); + /* We can only have one active profile */ + if (cur_profile) { + mutex_unlock(&profile_lock); + return -EEXIST; + } + + /* Sanity check the profile handler field are set */ + if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) || + !pprof->profile_set || !pprof->profile_get) { + mutex_unlock(&profile_lock); + return -EINVAL; + } + + err = sysfs_create_group(acpi_kobj, &platform_profile_group); + if (err) { + mutex_unlock(&profile_lock); + return err; + } + + cur_profile = pprof; + mutex_unlock(&profile_lock); + return 0; +} +EXPORT_SYMBOL_GPL(platform_profile_register); + +int platform_profile_remove(void) +{ + mutex_lock(&profile_lock); + if (!cur_profile) { + mutex_unlock(&profile_lock); + return -ENODEV; + } + + sysfs_remove_group(acpi_kobj, &platform_profile_group); + cur_profile = NULL; + mutex_unlock(&profile_lock); + return 0; +} +EXPORT_SYMBOL_GPL(platform_profile_remove); + +MODULE_AUTHOR("Mark Pearson "); +MODULE_LICENSE("GPL"); diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h new file mode 100644 index 000000000000..3623d7108421 --- /dev/null +++ b/include/linux/platform_profile.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Platform profile sysfs interface + * + * See Documentation/ABI/testing/sysfs-platform_profile.rst for more + * information. + */ + +#ifndef _PLATFORM_PROFILE_H_ +#define _PLATFORM_PROFILE_H_ + +#include + +/* + * If more options are added please update profile_names + * array in platform-profile.c and sysfs-platform-profile.rst + * documentation. + */ + +enum platform_profile_option { + PLATFORM_PROFILE_LOW_POWER, + PLATFORM_PROFILE_COOL, + PLATFORM_PROFILE_QUIET, + PLATFORM_PROFILE_BALANCED, + PLATFORM_PROFILE_PERFORMANCE, + PLATFORM_PROFILE_LAST, /*must always be last */ +}; + +struct platform_profile_handler { + unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; + int (*profile_get)(enum platform_profile_option *profile); + int (*profile_set)(enum platform_profile_option profile); +}; + +int platform_profile_register(const struct platform_profile_handler *pprof); +int platform_profile_remove(void); +void platform_profile_notify(void); + +#endif /*_PLATFORM_PROFILE_H_*/ From 9d56653d14cd5e545599cd9e3013daa17df50cd4 Mon Sep 17 00:00:00 2001 From: Jiaxun Yang Date: Mon, 25 Jan 2021 12:59:56 +0100 Subject: [PATCH 3/5] ACPI: platform-profile: Drop const qualifier for cur_profile Drop the const qualifier from the static global cur_profile pointer declaration. This is a preparation patch for passing the cur_profile pointer as parameter to the profile_get() and profile_set() callbacks so that drivers dynamically allocating their driver-data struct, with their platform_profile_handler struct embedded, can use this pointer to get to their driver-data. Note this also requires dropping the const from the pprof platform_profile_register() function argument. Dropping this const is not a problem, non of the queued up consumers of platform_profile_register() actually pass in a const pointer. Link: https://lore.kernel.org/linux-acpi/5e7a4d87-52ef-e487-9cc2-8e7094beaa08@redhat.com/ Link: https://lore.kernel.org/r/20210114073429.176462-2-jiaxun.yang@flygoat.com Suggested-by: Hans de Goede Signed-off-by: Jiaxun Yang [ hdegoede@redhat.com: Also remove const from platform_profile_register() ] Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/acpi/platform_profile.c | 4 ++-- include/linux/platform_profile.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c index 91be50a32cc8..f65c61db7921 100644 --- a/drivers/acpi/platform_profile.c +++ b/drivers/acpi/platform_profile.c @@ -9,7 +9,7 @@ #include #include -static const struct platform_profile_handler *cur_profile; +static struct platform_profile_handler *cur_profile; static DEFINE_MUTEX(profile_lock); static const char * const profile_names[] = { @@ -132,7 +132,7 @@ void platform_profile_notify(void) } EXPORT_SYMBOL_GPL(platform_profile_notify); -int platform_profile_register(const struct platform_profile_handler *pprof) +int platform_profile_register(struct platform_profile_handler *pprof) { int err; diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h index 3623d7108421..c797fdb3d91a 100644 --- a/include/linux/platform_profile.h +++ b/include/linux/platform_profile.h @@ -32,7 +32,7 @@ struct platform_profile_handler { int (*profile_set)(enum platform_profile_option profile); }; -int platform_profile_register(const struct platform_profile_handler *pprof); +int platform_profile_register(struct platform_profile_handler *pprof); int platform_profile_remove(void); void platform_profile_notify(void); From 84f9017c37c479c4f70456a645d24d2296ad2208 Mon Sep 17 00:00:00 2001 From: Jiaxun Yang Date: Mon, 25 Jan 2021 12:59:57 +0100 Subject: [PATCH 4/5] ACPI: platform-profile: Introduce object pointers to callbacks Add an object pointer to handler callbacks to avoid the need for drivers to have a global variable to get to their driver-data struct. Link: https://lore.kernel.org/linux-acpi/6a29f338-d9e4-150c-81dd-2ffb54f5bc35@redhat.com/ Link: https://lore.kernel.org/r/20210114073429.176462-3-jiaxun.yang@flygoat.com Signed-off-by: Jiaxun Yang Suggested-by: Hans de Goede Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/acpi/platform_profile.c | 4 ++-- include/linux/platform_profile.h | 6 ++++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c index f65c61db7921..80e9df427eb8 100644 --- a/drivers/acpi/platform_profile.c +++ b/drivers/acpi/platform_profile.c @@ -64,7 +64,7 @@ static ssize_t platform_profile_show(struct device *dev, return -ENODEV; } - err = cur_profile->profile_get(&profile); + err = cur_profile->profile_get(cur_profile, &profile); mutex_unlock(&profile_lock); if (err) return err; @@ -104,7 +104,7 @@ static ssize_t platform_profile_store(struct device *dev, return -EOPNOTSUPP; } - err = cur_profile->profile_set(i); + err = cur_profile->profile_set(cur_profile, i); mutex_unlock(&profile_lock); if (err) return err; diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h index c797fdb3d91a..a26542d53058 100644 --- a/include/linux/platform_profile.h +++ b/include/linux/platform_profile.h @@ -28,8 +28,10 @@ enum platform_profile_option { struct platform_profile_handler { unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)]; - int (*profile_get)(enum platform_profile_option *profile); - int (*profile_set)(enum platform_profile_option profile); + int (*profile_get)(struct platform_profile_handler *pprof, + enum platform_profile_option *profile); + int (*profile_set)(struct platform_profile_handler *pprof, + enum platform_profile_option profile); }; int platform_profile_register(struct platform_profile_handler *pprof); From 041142d7d25294c17d39552ae51c1d8d89434010 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 25 Jan 2021 20:09:09 +0100 Subject: [PATCH 5/5] ACPI: platform-profile: Fix possible deadlock in platform_profile_remove() After a rmmod thinkpad_acpi, lockdep pointed out this possible deadlock: Our _show and _store sysfs attr functions get called with the kn->active lock held for the sysfs attr and then take the profile_lock. sysfs_remove_group() also takes the kn->active lock for the sysfs attr, so if we call it with the profile_lock held, then we get an ABBA deadlock. platform_profile_remove() must only be called by drivers which have first *successfully* called platform_profile_register(). Anything else is a driver bug. So the check for cur_profile being set before calling sysfs_remove_group() is not necessary and it can be dropped. It is safe to call sysfs_remove_group() without holding the profile_lock since the attr-group group cannot be re-added until after we clear cur_profile. Change platform_profile_remove() to only hold the profile_lock while clearing the cur_profile, fixing the deadlock. Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/acpi/platform_profile.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c index 80e9df427eb8..4a59c5993bde 100644 --- a/drivers/acpi/platform_profile.c +++ b/drivers/acpi/platform_profile.c @@ -164,13 +164,9 @@ EXPORT_SYMBOL_GPL(platform_profile_register); int platform_profile_remove(void) { - mutex_lock(&profile_lock); - if (!cur_profile) { - mutex_unlock(&profile_lock); - return -ENODEV; - } - sysfs_remove_group(acpi_kobj, &platform_profile_group); + + mutex_lock(&profile_lock); cur_profile = NULL; mutex_unlock(&profile_lock); return 0;